Inflatable ice igloo

ABSTRACT

A rapidly erectable shelter makes use of ambient, subfreezing temperatures to protect men and equipment. Three flexible layers are arranged to define a pair of hemispherical shell-shaped chambers. Pressurized gas is vented to the inner chamber, which serves as a molding form for water being pumped into the outer chamber. The freezing of the water creates a rigid shell of ice and the inner gas filled chamber insulates the interior and prevents melted droplets of the ice shell from dripping into the interior. In warmer climates or under water, self-polymerizing thermoset resins or a concrete slurry is substituted for the pumped water with identical results. Irrespective which material is chosen, the shelter is quickly erected by unskilled labor and provides an air insulation inside the rigid shell.

United States Patent Stachiw Oct. 7, 1975 INFLATABLE ICE IGLOO 3,851,48712/1974 Lambertsen 52 2 [75] Inventor: Jerry D. Stachiw, Lakeside,Calif. FOREIGN PATENTS ()R APPLICATIONS [73] Assignee; The United Statesof America as 727,970 3/1955 United Kingdom 264/32 represented by theSecretary of the Navy, Washington, DC.

[22] Filed: Mar. 18, 1974 [21] App]. N0.: 452,312

[52] US. Cl 52/2; 52/80 [51] Int. Cl. E04B U345 [58] Field of Search52/2, 63, 80; 264/32, 35

[56] References Cited UNITED STATES PATENTS 2,649,101 8/1953 Suits 52/22,812,769 11/1957 Schaeferm 52/2 2,939,467 6/1960 Meyer 52/2 3,118,0101/1964 Harrington... 264/32 3,213,628 10/1965 Serota 52/2 3,258,8837/1966 Campanard. 52/2 3,357,142 12/1967 Farrer i. 52/2 3,388,509 6/1968Mora 52/2 3,611,648 10/1971 Barnett 52/2 3,643,910 2/1972 Hiefetz 264/323,660,951 5/1972 Cadwell.... 52/2 3,686,818 8/1972 Bini 52/2 3,726,9504/1973 Tarzi1lo..... 264/32 3,739,536 6/1973 Ward 52/63 PrimaryExaminer-Ernest R. Purser Assistant Examiner-Henry Raduazo Attorney,Agent, or Firm-Richard S. Sciascia; Ervin F. Johnston; Thomas GlennKeough [5 7 ABSTRACT A rapidly erectable shelter makes use of ambient,subfreezing temperatures to protect men and equipment. Three flexiblelayers are arranged to define a pair of hemispherical shell-shapedchambers. Pressurized gas is vented to the inner chamber, which servesas a molding form for water being pumped into the outer chamber. Thefreezing of the water creates a rigid shell of ice and the inner gasfilled chamber insulates the interior and prevents melted droplets ofthe ice shell from dripping into the interior. 1n warmer climates orunder water, self-polymerizing thermoset resins or a concrete slurry issubstituted for the pumped water with identical results. Irrespectivewhich material is chosen, the shelter is quickly erected by unskilledlabor and provides an air insulation inside the rigid shell.

5 Claims, 7 Drawing Figures U.S. Patent Oct. 7,1975 Shget 3 of3 3 99INFLATABLE ICE IGLOO STATEMENT OF GOVERNMENT INTEREST The inventiondescribed herein may be manufactured and used by or for the Governmentof the United States of America for governmental purposes without thepayment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION Portable shelters, particularly those whichare erectable upon short notice, are many and varied in design. Whiletents are lightweight and easy to put up, they leave much to be desiredin strong winds and extreme cold. Prefabricated structures employingrigid insulated panels have usually provided adequate shelter in ahostile environment. Unfortunately, however, hauling these structures toa work site creates a formidable logistics problem and a relativelyuncomplicated movement of men and equipment mushrooms into convoylikeproportions. The difficulties encountered during polar operations areaugmented by the burden imposed by the transport of the bulky, prefabshelters. Inflatable structures have been used to some degree of successand are, by and large, not as heavy and space consuming as the prefabstructures. Usually the inflatable shelters consist of a number ofair-filled sacks which are bonded and sewn together to form asausaged-shaped structure. The frequent polar storms pose a threat tothe conventional inflatable structures and, upon occasion, they areblown flat or uprooted by the severe winds. When gale winds strike,anchoring them with a considerable number of stakes often fails toprevent their being ripped apart. In addition, where the structures areto house machinery and equipment there is the ever present danger ofsnagging or puncturing and deflating the entire structure. One longappreciated and well known structure for arctic climes is the ice igloo. This ingenious habitat provides protection from intense cold andhigh winds. The ice igloo is one of the best engineering designs for apolar environment since it utilizes a readily available self-bonding icewhich has a high mechanical strength and a low heat transfercoefficient. However, the igloo has several drawbacks. The constructionof an igloo is a lengthy procedure and when the temperature inside theigloo is brought above freezing, the inside of the walls begins to melt.Water drips on the occupants and anything that happens to be inside theigloo and the humidity level rises. while the occupants can tolerate acertain amount of moisture, some electronic instrumentation cant, andits reliability falls considerably. Thus, there is a continuing need inthe state-of-the-art for a rapidly erectable structure for polar climeswhich is capable of affording adequate shelter and which is essentiallymoisture-free.

SUMMARY OF THE INVENTION The present invention is directed to providinga rapidly erectable shelter. A first hemispherical shellshaped chamberis coupled to a source of pressurized gas and after the first chamberhas been inflated, a second hemispherical shell-shaped chamber isdisposed adjacent to and is supported by the first chamber. Water ispumped into the second chamber and freezes into ice, thereby forming anice shell around the first air filled chamber. The ice shell withstandsthe effects of the harsh environment and the air-filled inner chamberinsulates the interior to prevent the melting of the ice shell.

It is a prime object of the invention to provide a rapidly erectableshelter.

Another object of the invention is to provide a rapidly erectableshelter constructed from the materials at hand.

Still another object is to provide a shelter ideally suited for polarclimes.

A further object is to provide a shelter which is fabricated from thematerials at hand.

Still another object is to provide a shelter employing an air-filledchamber as a molding surface for an adjacent chamber.

Still another object is to provide a rapidly erectable shelter having aninner air-filled chamber supporting and insulating an outer ice-filledchamber.

Yet another object is to provide a shelter which is compact and easilytransportable.

A further object is to provide a shelter employing an air-filled chamberas a molding form for a self polymerizing resin.

Another object is to provide a rapidly erectable shelter ideally suitedfor undersea deployment.

Another object is provide an undersea shelter employing a water-filledchamber as a molding form for concrete.

These and other objects of the invention will become more readilyapparent from the drawings when taken with the ensuing specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric depiction ofthe invention.

FIG. 2 is a cross-sectional representation of the invention generallytaken along lines 2-2 in FIG. 1.

FIG. 3 is a cross-sectional representation of the invention prior toerection.

FIG. 4 is a crosssectional representation showing the pressurizedchamber distended.

FIG. 5 is a cross-sectional representation showing the molding chamberbeing filled with the water partially frozen.

FIG. 5a shows a section of hardened resin.

FIG. 5b shows a section of set concrete.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,FIG. 1 shows the pre ferred embodiment of the invention in the form ofan inflatable ice igloo 10. Such a structure more than adequatelyprovides shelter for men and equipment in a harsh polar environment. Dueto its unique, sturdy construction, it is able to withstand a gale-likewind, yet there is no compromise in the speed at which it is erected.

Looking more particularly to FIG. 2, inflatable ice igloo 10 isfabricated from three main structural components, an inner fabric layer11, a middle fabric layer 12, and an outer fabric layer 13.

vThe materials chosen for the fabric layers, as well as other flexibleor fabric components to be described, are selected from commerciallyavailable fabrics. Since it is intended that the igloo is to be erectedin the cold outdoors, the fabric must remain flexible in subfreezingtemperatures. It must be heavy duty enough to resist puncturing andtearing during handling, yet, not so heavy as to sacrifice portability.Also, the material must resist deterioration by air and sunlight. Thereand other design parameters have led to the selection of a thirtythousandth of an inch neoprene-coated nylon fabric as a suitablematerial. Other state-of-the-art materials optionally are selected.

The three fabric layers are tailored in a hemisphcri cally-shapedconfiguration and are slightly differently dimensioned with respect toone another. After they are sewn and bonded together along their loweredges, a hemispherical shell-shaped pressurized chamber 14 is createdbetween inner fabric layer 11 and middle fabric layer 12 and, a slightlylarger hemispherical shellshaped molding chamber 15 is formed betweenmiddle fabric layer 12 and outer fabric layer 13. A fitting 16 ismounted to extend through inner fabric layer 1 l. The fitting is ofconventional design and functions as a passageway and retainer forpressurized fluid on its way to and in pressurized chamber 14. Asubstantially identical fitting 17 is located at the top of theinflatable ice igloo and serves to allow the filling of molding chamber15 with any one of a variety of liquids to be further described below.An auxiliary fitting 18 is mounted near the bottom rim of the moldingchamber and can be used either to facilitate the filling or the drainingof the chamber.

An entryway 19 is provided in the igloo and the fabric layers around theopening are sealed appropriately to maintain the integrity of the twochambers.

A hatch cover 20 is sized to cover the entryway and is joined to theouter surface of outer fabric layer 13 via a length of flexible strap20a. The hatch cover is made up of three interconnected flexible panels20b, 20c, and 20d. A fitting 20:: reaches through innermost wall 20d toallow the passage and retention of a pressurized fluid into the envelopecreated between walls 20c and 20d. Similarly, another fitting 20freaches through outer wall 20b and into the envelope created betweenwalls 20b and 200.

Since, in this preferred embodiment, it is intended that the ice igloobe used in polar or arctic regions, additional warmth in the interior isensured by the inclusion of an inflatable floor 21 suitably affixed tothe inner, middle, and outer fabric layers along its circumference. Thefloor is fashioned from upper and lower fabric layers 22 and 23, and isbonded onto the lower inner rim of inner fabric layer 11. A fitting 24,similar in design and function to the aforedescribed fittings,communicates with the space defined between the upper and lower fabriclayers. After the space is inflated, an insulative layer is providedbetween the interior of the igloo and the ice or snow on which the igloorests.

Because it is intended that the inflatable ice igloo will be used tosupport diving operations through the polar ice, a lower hatchway 25extends through the upper and lower fabric layers. An inflatable hatchcover 26 is sized to cover the hatchway and is formed from threeadjacent layers of flexible material. Hatch cover 26 differs from hatchcover 20 by the inclusion of an opening 26a and a single fitting 26b.The reason for this modification is that usually the entire interior ofhatch cover 26 is filled with pressurized gas. Pressurized gas is chosenfor its insulative properties and, because gas does not make the hatchcover excessively heavy.

On occasion, winds of gale force must be endured, and the weight of theigloo alone may not be sufficient to hold it in place. For this reason,a skirt 27, which is an extension of lower fabric layer 23, reaches outbeyond the limits of the outer fabric layer 13. Covering the skirt withdirt, ice or snow helps hold the structure in place, An annularretaining wall 28 is connected to the outermost rim of the skirt and,when distended via a conventional fitting 29, an annular trough iscreated between the retaining wall and the outer fabric layer. The sizeof the trough is such as to allow the retention of a sufficient amountof weight.

As an added feature, an opening 30 is made through the inner, middle andouter fabric layers near the top of the igloo. This opening serves as aduct for ventilation or for a stove pipe. An inflatable plug 31 isincluded to close the opening when ventilation or heating is not calledfor.

Referring more particularly to FIGS. 3, 4, and 5, a source ofpressurized gas 32 is coupled to fitting 16 by a hose 33. Pressurizedgas is fed to the hemispherical shell-shaped pressure chamber 14 andthis chamber is inflated, note FIG. 4. A sufficient pressure is fed tothe interior of the pressurized chamber to raise it to its hemisphericalconfiguration and to provide enough strength to support hemisphericalshell-shaped molding chamber 15 as it is filled with a suitablematerial. At this point, or later in the igloo erecting procedure,inflatable floor 21 is inflated via its fitting 24 and the hatch coversand the annular retaining wall are inflated.

When the aforedescribed structure is to be an ice igloo, the suitablebuilding material is water 34, see FIG. 5. A motor pump unit 35 draws inwater through a hose 36 and expels it through a hose 37. The oppositeend of hose 37 is connected to fitting 17 and water thereby reachesmolding chamber 15. Optionally, the motor pump unit is inside the iglooand hose 36 draws in water through hatchway 25.

Thickness of the ice, i.e. the width of the molding chamber is designedas a function of the desired size of the igloo and the amount of timethat it takes to erect the structure. A thin ice shell freezes fasterthan a thicker one, yet the thicker shell is more rugged. In eithercase, since there is a gradual pumping of water into the moldingchamber, there will be a gradual, progressive freezing of the liquidwater to the solid ice form 34a. A solid hemispherical shell being builtup in the molding chamber supports itself as it assumes thehemispherical shell-shaped configuration.

A sufficiently fast water flow rate should be maintained to avoidfreezing and blocking the flow of water in the upper portion of moldingchamber 15, before it is frozen in the lower portion. After the waterhas frozen to form a complete hemispherical ice shell, the source ofpressurized gas 32 is disconnected. The ice shell is of a shape andmaterial composition which bears its weight and the weight of the fabriclayers. Usually this weight is sufficient to hold the igloo in placeduring severe winds. If additional weight is needed, annular retainr 28is filled with either pressurized gas or water and the annular trough isfilled with water, snow, or any other material at hand.

The pressurized chamber 14 is left inflated to insulate Y the igloointerior from the frozen ice shell. The gasfiIled, pressurized chamberprevents, or at least retards, the condensation of moisture on the innersurface of inner fabric layer 11. Personnel and equipment are kept dryby the pressurized chamber.

The disclosed ice igloo is rapidly deployable in a matter of minutes byunskilled personnel. In addition, this shelter is fabricated frommaterials at hand, i.e., water, to reduce the logistics effort. Theinherent ruggedness of the neoprene coated nylon fabric from which theinner, middle, and outer layers are fashioned, provides a structurecapable of resisting damage during transport, erection, and use.

The structure thusly described is superior with respect to the typicalEskimo ice igloo; this invention is erectable in terms of minutes asopposed to hours for the Eskimo variety; experience has demonstratedthat the invention can be made much larger than a conventional Eskimoice igloo; and the invention is much warmer, since the captive air spacein pressurized chamber 14 separates the ice from the igloo interior.

In the embodiment just described, the ambient cold functions to freezethe water in the molding chamber to form a rigid, protective shell ofice. ln warmer climates, that is, climates having temperatures abovefreezing, other materials are substituted for water. Erection of amodified ice igloo is substantially as outlined above. The onlyexception is that a different type of material which changes from theliquid to the solid state is pumped into molding chamber 15. One suchmaterial is a self-polymerizing, thermoset resin'38 or solids having lowmelting temperatures, sulfur, for example. Although the expense of thesematerials is considerably greater than water, these materials may besuitable when the urgency for a rapidly erectable shelter offsets theexpense involved.

In a totally different environment the aforedescribed igloo functions toprovide an underwater habitat. The non-erected structure looks somewhatlike the invention in FIG. 3. The structure is positioned so that apiece of marine equipment, not shown, extends through hatchway 25. Next,the previously relied upon source of pressurized fluid, a motor pumpunit similar to motor pump units 35, is coupled to fitting l6. Ambientseawater 34 is drawn through the motor pump unit and fed to fitting 16.The pumped water causes the distention of pressurized chamber 14 and amolding form is created by chamber 14 on which molding chamber 15derives its shape.

A slurry 39 of concrete or bottom sediment is fed through fitting 16into the molding chamber. As is the case whenever concrete is beingpoured, care must be taken that the molding chamber is completely filledbefore the concrete slurry sets. Otherwise, the structural integrity ofthe igloo is compromised.

Because of the great weight of the hardened concrete shell, the igloo isstable even in strong currents. The igloo now is capable of shelteringmen and equipment. Optionally, the interior is gas filled for lifesupport or work details. When the igloo is gas filled, usually it iswise to add ballast on skirt 27 to offset the added buoyancy. Water ispumped from chamber 14 to help lower the humidity.

Obviously, many modifications and variations are possible in the lightof the above teachings and it is therefor understood that the inventionmay be practiced otherwise than specifically described.

What is claimed is:

l. A rapidly erectable shelter for subfreezing climes comprising: I

first means for enclosing a first shell-shaped chamber having a firstfitting communicating therewith, said first shell shaped chamber has awidth sufficient to provide insulation and to reduce the problemsassociated with condensation on the inside of said rapidly erectableshelter;

a source of pressurized gas coupled to said first fitting to distendsaid first enclosing means to define a first shell shaped chamber;

second means for enclosing a second shell-shaped chamber having a secondfitting communicating therewith, said second shell-shaped chamber issized to be larger than said first shell-shaped chamber to be disposedadjacent to and supported by said first enclosing means when said firstenclosing means is distended by said source of pressurized gas;

the first enclosing means and the second enclosing means are flexiblesheets shaped and arranged to form a three-walled, two-chamberedhemispherical shell; and

a source of water coupled to said second fitting for filling said secondshell-shaped chamber, said water freezes to the solid state after beingintroduced into said second shell-shaped chamber thereby forming thesupporting structure for said rapidly erectable shelter while said firstshellshaped chamber serves to insulate and to prevent droplets fromforming in the interior of said rapidly erectable shelter.

2. A rapidly erectable shelter according to claim 1 further including:

a pair of fabric layers for forming a floor for the three-walledhemispherical shell and being secured across the periphery thereof, thelayered floor having a fitting to allow its distention for insulatingthe interior of said rapidly erectable shelter.

3. A rapidly erectable shelter according to claim 2 further including:

a multilayered entryway for permitting access to the interior of saidshelter extending through said flexible sheets.

4. A rapidly erectable shelter according to claim 3 in which saidthree-walled hemispherical shell is provided with an opening forventilation and heating and the layered floor is provided with a floorhatch.

5. A rapidly erectable shelter according to claim 4 further including:

means connected to the layered floor for extending beyond said peripheryof said three-walled hemispherical shell and means carried on theextending means for defining an annular retainer and annular trough,said extending means and said annular retainer cooperating to collectsaid water to anchor said rapidly erectable

1. A rapidly erectable shelter for subfreezing climes comprising: firstmeans for enclosing a first shell-shaped chamber having a first fittingcommunicating therewith, said first shell-shaped chamber has a widthsufficient to provide insulation and to reduce the problems associatedwith condensation on the inside of said rapidly erectable shelter; asource of pressurized gas coupled to said first fitting to distend saidfirst enclosing means to define a first shell shaped chamber; secondmeans for enclosing a second shell-shaped chamber having a secondfitting communicating therewith, said second shellshaped chamber issized to be larger than said first shellshaped chamber to be disposedadjacent to and supported by said first enclosing means when said firstenclosing means is distended by said source of pressurized gas; thefirst enclosing means and the second enclosing means are flexible sheetsshaped and arranged to form a three-walled, two-chambered hemisphericalshell; and a source of water coupled to said second fitting for fillingsaid second shell-shaped chamber, said water freezes to the solid stateafter being introduced into said second shellshaped chamber therebyforming the supporting structure for said rapidly erectable shelterwhile said first shell-shaped chamber serves to insulate and to preventdroplets from forming in the interior of said rapidly erectable shelter.2. A rapidly erectable shelter according to claim 1 further including: apair of fabric layers for formiNg a floor for the three-walledhemispherical shell and being secured across the periphery thereof, thelayered floor having a fitting to allow its distention for insulatingthe interior of said rapidly erectable shelter.
 3. A rapidly erectableshelter according to claim 2 further including: a multilayered entrywayfor permitting access to the interior of said shelter extending throughsaid flexible sheets.
 4. A rapidly erectable shelter according to claim3 in which said three-walled hemispherical shell is provided with anopening for ventilation and heating and the layered floor is providedwith a floor hatch.
 5. A rapidly erectable shelter according to claim 4further including: means connected to the layered floor for extendingbeyond said periphery of said three-walled hemispherical shell and meanscarried on the extending means for defining an annular retainer andannular trough, said extending means and said annular retainercooperating to collect said water to anchor said rapidly erectableshelter.